Cement Manufacturers Association (CMA)

55 through volatilisation or leaching suggesting 193.2g (i.e., 460g x 0.42 = 193.2g) of nitrogen loss resulting in 266.8g (i.e., 460g – 193.2g = 266.8g) of usable nitrogen available for the plant. The dry weight of Azolla mostly comprises of protein (23 to 27%), followed by nitrogen (3- 6%), potassium (2-4.5%), phosphorus (0.5-0.9%) among other micronutrients. Therefore, 1 kg of dry azolla will have about 30g available nitrogen for plant utilisation, making 8.89 kg (i.e., 266.8g/30g = 8.89) of dry azolla equivalent to 1 kg urea in terms of nitrogen content. Further, emission intensity of urea is 4018.9 g CO2e/kg N. Therefore, 1 kg urea manufacturing emissions is 1072.24 gCO2e/kg urea (i.e., 4018.9 x .2668 = 1072.24). Thus, 1 kg urea is equivalent to 8.89 kg of dry azolla which in turn is equivalent to 127 kg fresh azolla in terms of nitrogen equivalence. Accordingly, it is derived that 1 kg fresh azolla displaces 8.44 gCO2e (i.e., 1072.24/127 = 8.44). Furthermore, for 1 m2 of azolla cultivation leads to harvested fresh azolla biomass of 71.36 kg/ m2-year and consequently the carbon captured through such biomass growth (L11) as 7.7 kgCO2e/ m2-year (i.e., 71.36 x 0.107898 = 7.7). Accordingly, reduction in urea manufacturing emissions (L21) is 602.31 gCO2e /m2-year (i.e., 71.36 x 8.44 = 602.31). Therefore, the effective emissions captured and offset (L11 + L21) is 8.30 kgCO2e/ m2-year. Results The azolla harvests have been 1947 kg (December 2022), 2201 kg (January 2023) and 3869 kg (February) from a natural waterbody of approximately 2000 m2 using only single- superphosphate fertiliser as input and lime as a coagulating agent for initial water treatment. These harvests are equivalent to 210.08 kg, 237.48 kg and 417.46 kg of atmospheric CO2 sequestered by azolla cultivation. A vertical azolla cultivation unit was set up at New Delhi with a cumulative area of 1.78 m2 across 23 containers. The harvest data for 31 days, from 6th May to 6th June 2023 has been shown in Fig. 1. The normalised production rate is 83.5 g m-2 day-1 of wet biomass. Model Calculation: Azonian Process for Decarbonising the Indian Cement Industry Annual emissions from the Indian cement industry = 200 MtCO2e/year L11 carbon capture efficiency of the Azonian Process = 7.7 kgCO2e/m2-year Effective area required for net-zero attainment through offsets = 25,974.026 km2 Degraded land in India = 9,00,000 km2 Percentage of degraded land required to decarbonise the Indian cement Industry = 2.88% Financial Viability of Decentralised Carbon Capture 331 273 236 453 408 101 208 899 122 623 316 642 604 840 1293 1701 1802 2010 2909 3031 3654 3970 4612 Day 1 2 3 6 10 11 14 18 21 23 30 Harvest Cumulative Figure.1: Azolla harvest data (grams) from vertical setup